User blog comment:Flia/Canon material/@comment-1512913-20111207232529/@comment-775152-20111208035458

I hate to be a stickler, but Dante didn't meet either of them. Arkham monitored Dante's actions through others such as Alice and Mad Hatter, but they never met face-to-face. And although Mary and Dante were in the same room together several times, Dante never noticed or spoke to her. In the Bullseye Bar, she was playing pool while he was talking to the bartender, and in his office, she hid in the bathroom but he never found her.

He did, however, meet Vergil before the game events. It's been a while since I've played, and I can't quite remember what their reactions to each other were in-game. I don't think it was much of a surprise to either, though.